Apparatus comprising a perforated drum

Abstract

A perforated drum coating machine which can readily be set up so as to be suitable for the coating of either tablets or the like, or spheroids. The machine contains at least one securing means which is attachable to the perforated drum, and at least one mesh member consisting of suitable mesh which is edged with thin springy material, and a strip of deformable rubber or plastics material which is positioned against the inward facing part of the edge of the perforated part of the drum at two or more arcuate portions thereof. The or each securing means is adapted to engage with and secure, on the inside of the drum, two mesh member edges. The total area of the mesh member(s) is essentially the same as the area of the perforated part of the drum. The deformable strips are positioned between at least two mesh member edges and the said arcuate portions of the perforated drum. The edges of the mesh member(s), which are adjacent the deformable strips which are themselves adjacent the said arcuate portions, are slightly over-long (i.e. in a circumferential sense), and they are sprung in an outward direction so as to be a tight fit against the deformable strips and, through said strips, against the arcuate edges of the perforated part of the drum.

What we claim is: 
     
       1. A modified perforated drum coating machine which contains at least one securing means which is attachable to the perforated drum, and at least one mesh member consisting of suitably sized mesh, each outer edge of which is attached to a strip of thin springy material, and a strip of deformable rubber or plastics material which is positioned against the inward facing part of the edge of the perforated part of the drum at at least two arcuate portions thereof, the or each securing means being adapted to engage with and secure, on the inside of the drum, two non-adjacent mesh member edges, the edges of the mesh member or members, which edges are adjacent the said deformable strips which are themselves adjacent the said arcuate portions of the perforated drum, being slightly over-long and when secured in position the or each mesh member is sprung in an outward direction against the said deformable strips, and wherein the total area of the mesh member or members is essentially the same as the area of the perforated part of the drum. 
     
     
       2. A machine as claimed in claim 1 in which the securing means and the mesh member or members comprise stainless steel and the deformable rubber or plastics material is foam rubber strip. 
     
     
       3. A machine as claimed in claim 1 in which there are three securing means, positioned symmetrically around the perforated drum, and three equal-sized mesh members. 
     
     
       4. A machine as claimed in claim 1 in which, when the deformable strips, mesh member or members, and securing means, are securely fixed into position, the inward facing edges of the mesh member or members are covered with a suitable metallised adhesive tape in such a way as to give a smooth surface running from the mesh, over the edge of the or each mesh member, and on to the adjacent non-perforated inner surface of the drum. 
     
     
       5. A machine as claimed in claim 4 in which any voids on the outward side of the said metallised tape are filled with self-adhesive plastics tubing. 
     
     
       6. A perforated drum coating machine comprising at least two mesh member-securing means spaced circumferentially along the inside of the perforated drum, at least two mesh members of suitably sized mesh different from the perforations of the perforated drum, each outer edge of each mesh member being attached to a strip of thin springy material, each of said mesh members being secured by and between said spaced securing means on the inside of the drum and so positioned as to overlay all of the perforated area of the drum, a strip of deformable rubber or plastic material positioned between each edge of each mesh member and the inside of the perforated drum, the mesh member edges adjacent to the arcuate part of the drum being slightly overlong so that each mesh member may be slightly bowed inwardly when placed between the spaced securing means but is sufficiently springy that it may be sprung outwardly into a tightly secured position between said securing means, each mesh member when sprung outwardly into the secured position having its edges resting firmly against said deformable strips.